The invention relates to apparatus for damping vibrations in power trains of motor vehicles, and more particularly to improvements in vibration damping apparatus of the type wherein a first flywheel is connectable to the internal combustion engine of the vehicle, a second flywheel is connectable with the input element of the variable-speed transmission of the vehicle (preferably by way of a friction clutch), and one or more dampers are arranged to operate between the first and second flywheels. As a rule, the dampers contain energy storing elements which react against the first flywheel and bear against a component which is substantially non-rotatably but axially movably connected with the second flywheel, for example, by way of a toothed coupling, and is mounted for angular movement relative to the first flywheel.
Commonly owned copending patent application Ser. No. 069,611 (filed Jul. 2, 1987 by Johann Jackel for "Apparatus for damping torsional vibrations" and now U.S. Pat. No. 4,946,420) discloses an apparatus wherein the damper means between the flywheels comprises energy storing means in the torm of coil springs which are installed in a chamber of one of the flywheels. The damper means further comprises a hydraulic damper. A component of the damper means resembles a flange and is installed between the flywheels with freedom of axial movement so as to compensate for the sum of tolerance of all parts of the apparatus as well as to establish with the adjacent parts an axial clearance (such clearance is necessary or desirable for proper operation of the hydraulic damper). The component can turn relative to the first flywheel and is connected with the second flywheel by means of a toothed coupling which permits the component to move axially of and between the two flywheels. It is necessary to ensure that the teeth of the coupling mate with a certain amount of play in order to compensate for manufacturing tolerances as well as to permit convenient assembly of the apparatus.
It has been found that, as the wear upon the two halves of the coupling progresses and the play between the teeth of such parts increases accordingly, the coupling generates excessive noise. In order to reduce the noise, a further prior proposal involves the utilization of rivets to fixedly secure the radially innermost portion of the component to the second flywheel. This necessitates an increase of clearances between the two sides of the component and the adjacent parts in order to avoid jamming of the damper. Excessive clearances between the component which is riveted to the second flywheel and the adjacent parts of the apparatus are undesirable for obvious reasons.